In a typical cellular radio system, wireless terminals (also referred to as wireless mobile terminals, user terminals, user equipment nodes or UEs, mobile stations, etc.) communicate via a radio access network (RAN) with one or more core networks. The RAN covers a geographical area which is divided into cell areas, with each cell area being served by a RAN node, also referred to as a radio base station (BS). A cell area is a geographical area where radio coverage is provided by the base station at a base station site. The base stations communicate through radio communication channels with wireless terminals within the coverage area of the base stations. The type of radio communication channels utilized between the base station and the wireless terminals define the radio access technology (RAT). There are radio access technologies that support circuit-switched and packet-switched operations, for example CDMA (code division multiple access) or GSM (Global System for Mobile Communications), and there are radio access technologies that support high-rate, spectrally efficient data operations, for example High Rate Packet Data (HRPD), Long Term Evolution (LTE), and/or Third Generation Partnership Project (3GPP/3GPP2).
In CDMA networks according to ANSI standards (including the ANSI-41 standard), for example, a base station controller (BSC) or controllers (BSCs) may control a plurality of base stations over a coverage area of the network, and communications may be switched through a pool of mobile switching/service centers (MSCs) between the BSC(s) and a core network (CN) and/or a public switched telephone network (PSTN). A pool of MSCs in such a network may provide redundancy in the event that one or more MSCs are unavailable for use. For example, a pool of separately located MSCs may continue network operations (possibly at reduced network capacity) even if one or more of the MSCs of the pool is unavailable due to power outage, malfunction, maintenance, destruction, etc.
Accordingly, multiple MSCs of a pool may simultaneously serve wireless terminals in a wide geographic region using a common BSC or using a common set of BSCs. Such MSC pooling may thus provide increased capacity available to cover wireless terminals in a particular geographic area and also provide a mechanism by which coverage may continue when one or more of the MSCs is out-of-service or otherwise unavailable.
While existing standards may define operations of MSCs within a pool, communications from network elements outside the pool may fail due to loss of service and/or unavailability of an MSC with which such outside network elements attempt to communicate. Accordingly, there continues to exist a need in the art for methods of operating network elements to route communications to/through pooled MSCs.